1. Field of the Invention
The invention relates to an electric power conversion device and, more particularly, to an electric power conversion device that is capable of performing a detection of whether or not a current flowing through a switching element is a short circuit current.
2. Description of Related Art
It is preferable that a detection of whether or not a current flowing through a switching element is a short circuit current is performed in a quick manner.
As an example, Japanese Patent Application Publication No. 2001-169533 (JP 2001-169533 A) discloses a Rogowski coil being disposed for detection of a current change rate of a main current that flows through the switching element of an electric power conversion device.
In the method for placing the Rogowski coil in series in the switching element, an induction voltage that is generated in the Rogowski coil is a temporal differentiation of the current, and thus it can be detected within a short period of time whether or not the current flowing through the switching element is the short circuit current. An erroneous detection arises when an external magnetic field is in the Rogowski coil as a noise. In the Rogowski coil, however, a loop has to be made with the coil in a current path of an object to be measured, which results in an increase in cost and an increase in mounting area.